The present invention relates to a yarn feeding device of a flat knitting machine used for plating.
When plating is performed by using a flat knitting machine, a plating carrier or equivalent is used for knitting. The plating carrier has, at a lower end thereof, yarn feeding means having a hole for a main yarn shown as a front yarn to pass through and a hole for a plating yarn shown as a back yarn to pass through, respectively. In plating, the yarns are aligned in the yarn feeding means and fed therefrom to knitting needles in the feeding order of the main yarn and the plating yarn with respect to a traveling direction of a carrier so that the main yarn can show on the front side of the fabric.
As shown in FIG. 14, some known plating carriers have yarn feeding means 200 having, at a center portion thereof, a hole 202 of circular cross section for the main yarn to pass through and an arched slot 204, encircling the circular hole 202 in semicircular, for the plating yarn to pass through. The plating carrier of this type is so designed that when the carrier changes in traveling direction, the plating yarn can pass through the arched slot 204, so that the main yarn and the plating yarn are caused to change over positions, depending on the traveling direction of the carrier.
The other known plating carriers have yarn feeding means 206 having a hole 208 for the main yarn to pass through and a hole 210 for the plating yarn to pass through, as shown in FIG. 15 showing a front view of the yarn feeding means 206. The plating carrier of this type is so designed that the yarn feeding means 206 can be reversed 180 degree to cause the main yarn and the plating yarn to change over positions with respect to the traveling direction of the carrier.
The means for reversing the yarn feeding means 206 that may be used include, for example a rack-and-pinion. Also, the means for moving the rack in reciprocation that may be used include, for example, friction resistance against a yarn guide rail and a motor drive.
The means for reversing the yarn feeding means by the motor drive is known from Japanese Laid-open (Unexamined) Patent Publication No. Sho 51(1976)-23352. This publication discloses a yarn feeding device wherein a gear is rotated by a pawl mounted on a rail of the knitting machine body, to turn on a micro switch to drive the motor, whereby the rack is moved in reciprocation to rotate the pinion so as to rotate the yarn feeding means 180 degree.
According to (i) the former conventional plating carrier wherein the yarn feeding means 200 having the circular hole 202 for the main yarn to pass through and the arched slot 204, encircling the circular hole 202 in a semicircular, for the plating yarn to pass through are so designed that when the carrier changes in traveling direction, the plating yarn can pass through the arched slot 204 to cause the main yarn and the plating yarn to change over positions in the traveling direction of the carrier and (ii) the latter conventional plating carriers wherein the yarn feeding means 206 at the lower end portion of the plating carrier is reversed through the use of friction resistance against yarn guide rail or equivalent, to cause the main yarn and the plating yarn to change over positions in the traveling direction of the carrier, the positions of the main yarn and the plating yarn depend on the traveling direction of the carrier.
Consequently, these conventional plating carriers cannot be used, for example, in such a knitting that the plating yarn shows on the front side of the fabric in the process of knitting, in order to change the pattern in the middle of the knitting width.
In the case of the plating carrier wherein the yarn feeding means is reversed by the motor drive, as disclosed by Japanese Laid-open (Unexamined) Patent Publication No. Sho 51(1976)-23352, the pawl serving to drive the motor to rotate the yarn feeding means must be mounted in advance on the yarn guide rail. In addition, although this plating carrier can be used for knitting a fabric having some regular pattern, such as a checkered pattern or a striped pattern, this plating carrier does not enable the main yarn and the plating yarn to change over positions at any desired positions, when knitting a fabric of such a pattern that the location at which the yarn feeding means is reversed varies depending on the knitting courses. Besides, a dedicated motor for reversing the yarn feeding means must be incorporated and, as a result of this, the yarn carrier is complicated and increased in size and weight.
In the light of the drawbacks mentioned above, the present invention has been made. It is the object of the invention to provide a yarn feeding device of a flat knitting machine that enables yarn feeding means of a yarn carrier to be reversed at any selective location, irrespective of the direction of knitting.
The present invention provides a yarn feeding device of a flat knitting machine comprising at least a pair of front and back needle beds which are so disposed that their front ends confront each other in an abutment relation; a number of knitting needles arranged in line on the needle beds in such a manner as to be freely advanced and retracted; a yarn guide rail arranged over the needle beds to extend in parallel with a longitudinal dimension of the needle beds; a yarn carrier for feeding a yarn to the knitting needle which is movably arranged in the yarn guide rail; carrier accompanying means including an accompanying member for releasing the yarn carrier from accompaniment at any position of the needle beds, the yarn carrier comprising:
a carrier base having, at an upper end thereof on the center side, an engaging portion engageable with the accompanying member of the carrier accompanying means and supported on the yarn guide rail in such a manner as to move in reciprocation along the longitudinal dimension of the needle beds;
reciprocating means supported on the carrier base in such a manner as to move in reciprocation with respect to a traveling direction of the carrier base and having, at an outside of the engaging portion of the carrier base with respect to the traveling direction, an engaging surface temporarily engageable with the accompanying member of the carrier accompanying means;
feeder means having, at its front end, a main-yarn feeding hole and a plating-yarn feeding hole, extending vertically downwardly from the carrier base, and supporting at least one of the yarn feeding holes in such a manner as to freely rotatable about an axis in a longitudinal direction of the feeder means; and
movement conversion means for converting reciprocating movement of the reciprocating means into rotation movement of the yarn feeding holes provided in the feeder means in such a manner that when the reciprocating means is moved with its engaging surface engaged with the accompanying member, the yarn feeding holes of the feeder means can be rotationally displaced to change a positional relationship between the main-yarn feeding hole and the plating-yarn feeding hole over a needle bed gap between the needle beds,
wherein the carrier accompanying means is electrically controlled so that when the yarn carrier is accompanied by the accompanying member and/or is released from the accompaniment, the carrier accompanying means can be selectively engaged with or disengaged from the engaging surface of the reciprocating means.
It is preferable that the movement conversion means comprises a rotary cam that is rotated by movement of the reciprocating means and an auxiliary rotary cam arranged under or over the rotary cam; the rotary cam is rotated a predetermined turn by the movement of the reciprocating means; and then the rotary cam or the auxiliary rotary cam is vertically moved to bring the auxiliary rotary cam into abutment with the rotary cam, whereby the rotary cam is rotated the remaining turn until the feeder means is reversed.